/*
 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; version 2 of the
 * License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301  USA
 */

#include "shellcore/shell_notifications.h"

namespace shcore
{
  ShellNotifications* ShellNotifications::_instance = NULL;

  NotificationObserver::~NotificationObserver()
  {
    std::list<std::string>::iterator it, end = _notifications.end();

    for (it = _notifications.begin(); it != end; it++)
      ShellNotifications::get()->remove_observer(this, *it);

    _notifications.clear();
  }

  void NotificationObserver::observe_notification(const std::string& notification)
  {
    if (ShellNotifications::get()->add_observer(this, notification))
      _notifications.push_back(notification);
  }

  void NotificationObserver::ignore_notification(const std::string& notification)
  {
    if (ShellNotifications::get()->remove_observer(this, notification))
      _notifications.remove(notification);
  }

  ShellNotifications *ShellNotifications::get()
  {
    if (!_instance)
      _instance = new ShellNotifications();

    return _instance;
  }

  ShellNotifications::~ShellNotifications()
  {
  }

  bool ShellNotifications::add_observer(NotificationObserver *observer, const std::string &notification)
  {
    bool ret_val = false;

    // Gets the observer list for the given notification
    // creates the list if it is the first observer
    if (_observers.find(notification) == _observers.end())
      _observers[notification] = new ObserverList();

    // Adds the observer if it does not exists already
    ObserverList *list = _observers[notification];
    ret_val = std::find(list->begin(), list->end(), observer) == list->end();
    if (ret_val)
      _observers[notification]->push_back(observer);

    return ret_val;
  }

  bool ShellNotifications::remove_observer(NotificationObserver *observer, const std::string &notification)
  {
    bool ret_val = false;

    if (_observers.find(notification) != _observers.end())
    {
      ObserverList *list = _observers[notification];

      ObserverList::iterator it = list->begin();
      while (it != list->end())
      {
        if (*it == observer)
        {
          ret_val = true;
          list->erase(it);
          break;
        }
        else
          it++;
      }

      if (list->size() == 0)
      {
        delete list;
        _observers.erase(notification);
      }
    }

    return ret_val;
  }

  void ShellNotifications::notify(const std::string &name, shcore::Object_bridge_ref sender, shcore::Value::Map_type_ref data)
  {
    if (_observers.find(name) != _observers.end())
    {
      ObserverList *list = _observers[name];

      ObserverList::iterator it = list->begin();
      while (it != list->end())
      {
        (*it)->handle_notification(name, sender, data);
        it++;
      }
    }
  };

  void ShellNotifications::notify(const std::string &name, shcore::Object_bridge_ref sender)
  {
    notify(name, sender, shcore::Value::Map_type_ref());
  }
};